The present invention relates to a manufacturing method for electronic component-mounted components to manufacture electronic component-mounted components by mounting electronic components such as semiconductor elements to a base, a manufacturing method for electronic component-mounted completed products with the electronic component-mounted components, and electronic component-mounted completed products with the electronic component-mounted components. The electronic component-mounted completed product with the electronic component-mounted components corresponds to stack modules, memory cards, non-contact IC cards and the like.
A conventional manufacturing method for an electronic component-mounted completed product which has, for example, a plurality of semiconductor elements, capacitors, resistors and the like passive components mounted on one carrier substrate will be described below with reference to FIGS. 11 and 12.
Conventionally, in a CSP (chip size package), an MCM (multi chip module) or a memory module having semiconductor elements, electronic components and the like passive components mounted thereon, a mounting method has been employed for the semiconductor elements, by which the semiconductor elements are pressed with heat in contact onto the carrier substrate via a conductive adhesive or a conductive sheet. For the electronic components, a method has been employed by which the electronic components are mounted in a predetermined circuit pattern by reflowing a solder paste printed in the predetermined circuit pattern on the carrier substrate.
More specifically, as shown in FIG. 11, projection-shaped electrodes 2 formed at electrode pads 1a of a semiconductor element 1 are electrically connected via an anisotropic conductive adhesive 15 to electrodes 3 on a carrier substrate 6. A sealing material 5 is injected and hardened between the semiconductor element 1 and the carrier substrate 6 so as to improve the jointing strength therebetween. At the opposite side of a mounting face of the semiconductor element 1, electrodes 4 of the carrier substrate 6 and predetermined electrodes 8 of a motherboard 11 are connected with each other via a solder paste 7, whereby the carrier substrate 6 is connected to the motherboard 11. To the electrodes 8 of the motherboard 11 are connected electrodes 10 of an electronic component 9 via the solder paste 7.
Reference numeral 13 denotes a through hole for electrically connecting the electrode 8 on a front face of the motherboard 11 to a circuit pattern 12 at a rear face of the motherboard 11. The through hole 13 is unnecessary in the case of a product without the circuit pattern 12.
A memory module 14 as an example of the electronic component-mounted completed product with the electronic component-mounted components formed in the above configuration.
As shown in FIG. 12, in a manufacturing process for the memory module 14, the solder paste 7 is applied by printing onto predetermined electrodes 8 on the motherboard 11 in a first step (denoted by “S” in the drawing) 1. Printing the solder paste 7 is normally carried out by screen printing. In a next step 2, the carrier substrate 6 with the semiconductor element 1 loaded and the electronic component 9 are registered onto the solder paste 7 formed by the printing respectively. In a succeeding step 3, the carrier substrate 6 with the semiconductor element 1, and the motherboard 11 with the electronic component 9 are passed through a reflow furnace to melt the solder paste 7. The solder paste is then hardened.
The memory module 14 as the electronic component-mounted completed product is manufactured in the manner as above (for instance, with reference to a non-patent document 1: “Board Reliability of Ceramic CSP by Various Kinds of Solder Material” by Satoh, et al. at a symposium on “Microjoints and Assembly Technology in Electronics” on Feb. 4–5, 2002, on page 133.)
The above-described conventional manufacturing method for the electronic component-mounted completed product with the electronic component-mounted components, and the configuration of the MCM or memory module as the electronic component-mounted completed product manufactured by the manufacturing method have the following problems that have yet to be solved.
Since electronic components such as the CSP are loaded on the motherboard 11, the module is increased in size in a thickness direction and thus cannot respond to the latest need for products to be thinned. The module is prone to be subject to effects of bending because of the increased thickness and is difficult to be made flexible and applicable to a surface or the like shape. In addition, the motherboard 11 necessitates a region for loading the electronic component 9 and the carrier substrate 6. Consequently, the number of electronic components loadable on one motherboard 11 and a region for forming the circuit pattern are determined by the size of the motherboard 11, which hinders efforts to meet the recent need of miniaturization of the motherboard 11.
Furthermore, since the semiconductor element 1 and the solder paste 7 are directly exposed to the atmosphere, oxidation takes place when the element and the solder paste are used under a high-temperature and high-humidity environment, often resulting in an electric short circuit, imperfect contact, a decrease in jointing strength and the like. Also because of the uneven temperature in the reflow furnace, the motherboard 11 cannot be made large-size. The productivity is poor although a batch process is a mainstream.